This invention relates to sliding jaw wrenches, particularly pipe wrenches in which a movable jaw has a degree of freedom to rock or float relative to a stationary jaw, and the jaws are relatively inclined in order to grip around a pipe or the like.
In wrenches of the sliding jaw-type, the movable jaw commonly is formed on a elongate shank which is mounted for lengthwise movement, to adjust the jaw opening, on a wrench handle, which is formed with the stationary jaw, and a screw mechanism with a rotary actuator is commonly provided between the shank and the handle to effect adjustable movements of the movable jaw. In such wrenches, both hands may be needed to adjust the jaws, and the screw mechanism may be difficult to operate should dirt get in the threads or should the operator's fingers be stiff or slippery.
The parent application provides a sliding jaw wrench having an alternative type of adjustment mechanism which is simpler to operate, and not as subject to the difficulties outlined above. Thus, the parent application discloses a sliding jaw wrench comprising a wrench handle, a stationary jaw on the wrench handle, an elongate shank formed with a movable jaw, the shank being mounted for movement in a pocket formed in the handle to adjust the degree of opening of the jaws, a longitudinal series of transverse recesses formed along one edge of the shank, a transverse mounting pin mounted in the handle for movement into and out of engagement with respective ones of the recesses for respectively retaining the shank in position and releasing the shank for adjustment of the jaws, an actuating assembly associated with the handle for moving the locking pin, and a nipple formed on a wall of the handle defining the pocket for engaging an opposite edge of the shank and for providing rocking of the shank in the pocket facilitating gripping of the workpiece between the jaws.
A wrench in accordance with the parent application can be adjusted with one hand, without a user having to release his or her grip on the wrench handle simply by applying thumb or finger pressure on a sprung lever forming part of the actuator assembly, and flicking or otherwise moving the movable jaw to the required position. However, in a wrench of this type, since the degree of opening of the jaws is dependent on the engagement of the locking pin in a selected recess, and since there are spaces between the recesses, adjustment of the jaws is not infinite, but is incremental. A situation may therefore arise in which when tightening the wrench onto an article such as a pipe, neither one of a pair of adjacent recesses gives the precise degree of jaw opening required for an absolutely positive and optimum fit on the pipe.
It is an object of the present invention to provide, in a sliding jaw-type wrench having incremental adjustment means for changing the degree of jaw opening, a fine adjustment mechanism whereby a more accurate fit of the wrench jaws on a object to be gripped can be obtained where such fit would otherwise correspond with a jaw opening position which is between a pair of incremental jaw movements.